A persistent problem of the mathematics teacher is the motivation of students especially those not particularly interested in numerical work. In this paper we present a notational device for analysing relationships based on binary notation and show its application to the problem of incest. The authors developed this theory in the course of their study of the rabbinic law on this subject and present this application here, though it could be applied to any legal system. It is hoped that the use of this approach may be useful to introduce mathematical modes of thought to previously uninterested pupils.